Navitron Renewable Energy and Sustainability Forum

HEAT PUMPS & Geothermal Energy => Heat Pumps => Topic started by: Eccentric Dyslexic on November 27, 2009, 11:25:45 AM



Title: Brine antifreeze?
Post by: Eccentric Dyslexic on November 27, 2009, 11:25:45 AM
How do you make this up for a ground loop?  I understand its better than using glycol based anti freezes?

cheers!

steve


Title: Re: Brine antifreeze?
Post by: dhaslam on November 27, 2009, 11:51:41 AM
I think that the  term 'brine'  is just a misuse of the word in this  context.  It is just a normal  antifreeze mix.    Are  your return temperatures getting down  to freezing  at present?   


Title: Re: Brine antifreeze?
Post by: Eccentric Dyslexic on November 27, 2009, 12:12:01 PM
about to fill the loop stage ATM, but am expecting flow out to GL to be about 4c, but can ice form inside of the evaperator reducing efficency if i dont use antifreeze?

steve


Title: Re: Brine antifreeze?
Post by: dhaslam on November 27, 2009, 01:10:56 PM
As far as I know the reason for antifreeze is to  prevent freezing when the system is static.    Once the water is flowing  it won't be freezing except  possibly  on exiting the heat exchanger and of course if the pump stops ice will form.  It cannot freeze when moving.    It is  advisable to  put in some antifreeze anyway.  I presume you can use  ethylene glycol as used for cars and costs about 2 per litre.                 


Title: Re: Brine antifreeze?
Post by: djh on November 27, 2009, 01:28:16 PM
Don't the manufacturer of your heat pump provide specifications for the fill?  Presumably as well as not freezing, the liquid should have good heat transfer properties and be compatible with the device from a corrosion point of view.


Title: Re: Brine antifreeze?
Post by: PSSSSD on November 27, 2009, 04:52:42 PM
I agree, I'd check with the manufacturers and just to add to "djh"s reply, some pumps rely on the lubricating qualities of the additive. Not forgetting amongst other things its anti-fungal properties too. The title antifreeze only really describes one aspect of the treatment.

Cheers


Title: Re: Brine antifreeze?
Post by: baker on December 14, 2009, 09:48:15 PM
i am not a expert
-20 protection
most heat pumps can work down to -10
is is ground loops?  or bore holes
and will be in that area if horizontal ground loops  is the source at the end of winter
if ice starts to form in the plate heat exchanger which it can
it can freeze and split and in turn brake into the  ref compressor
and that is that  sh*tfan:
   antifreeze  expensive
polye, antifreeze is poison   caution with/containers/system design
polyg antifreeze is ok 
 


Title: Re: Brine antifreeze?
Post by: Eccentric Dyslexic on December 30, 2009, 12:12:13 PM
Just an update to this thread, i used car anti freeze in the loops, i am getting out-to-loop temps of -5c so antifreeze is defo needed.  My loops are protected down to -20c as the pressure guages on my HP indicate temps of -20c on the surfaces of the evaporator piping.

steve


Title: Re: Brine antifreeze?
Post by: wrigpm on September 19, 2010, 11:49:29 AM
I used Hydratech Coolflow IG in ours

Paul


Title: Re: Brine antifreeze?
Post by: Philip R on September 20, 2010, 09:20:54 PM
You must not use automotive poly(ethylene) glycol antifreeze in your groundloop. It is highly toxic, not very biodegradable and will contaminate the groundwater should it ever leak out.
If the Environment agency ever found one out about a leak, the result would be likely to be a trip to the Crown court, an enormous fine and a possible stretch inside.

Follow Manufacturers instructions, i.e. use what they recommend, i.e. Polypropylene glycol solution.


Title: Re: Brine antifreeze?
Post by: wrigpm on September 20, 2010, 09:59:46 PM
Philip

Not sure where you got your info from but the Environment Agency data states:-

# Ethylene glycol is itself Biodegradable
# Ethylene glycol in air will break down in about 10 days.
# Ethylene glycol in water and in soil will breakdown within several days to a few weeks.

It is however, very toxic by ingestion having an oral LDLO of only 786 mg/kg i.e. about 62g will kill you!


Title: Re: Brine antifreeze?
Post by: mespilus on September 20, 2010, 11:25:49 PM
What's a 'poly' between friends?

http://en.wikipedia.org/wiki/Ethylene_glycol_poisoning

and

http://en.wikipedia.org/wiki/Polyethylene_glycol


Title: Re: Brine antifreeze?
Post by: Philip R on September 21, 2010, 11:11:13 PM
In answer to the input from wrigpm and mespilus.

I had the view that Ethylene Glycol was much less biodegradeable than your data shows. I stand corrected.
EG in soil/ groundwater can still remain long enough to penetrate water courses. With modern water treatment plant, i.e. activated charcoal filters, found in newer treatment works, the likelihood of it enterring the drinking water supply is very small.

With respect to my comments about the Environment Agency. In my former employment, an incident occurred where a substantial quantity of fuel oil leaked from an underground pipe. Despite a cleanup campaign and an admission to the EA and HSE that the leak had occurred, a trip to the court resulted, a substantial fine was levied and the possibibility of a custodial sentences was also mentioned.

I appreciate that fuel oil and the antifreeze componds are quite different in toxicity and biodegradability. They are still toxic and leaks would not be tolerated.

The "poly" referred to Polyethylene or polypropylene glycols (PPE & PPG). I have seen this in literature about various antifreeze products. Maybe incorrectly labelled and subsequently incorrectly communicated by myself.  However reading the wiki links, it would have been correct to say that PE and PG are the antifreeze compounds, not PPE and PPG, as these are the polyimerised molecules of aforementioned PE and PG used as chemical intermediates for the synthesis of all kinds of products.



Title: Re: Brine antifreeze?
Post by: mespilus on September 21, 2010, 11:58:42 PM
In addition to the monomers and polymers
of
ethylene and/or propylene glycol

we also have the dimers:

http://en.wikipedia.org/wiki/Diethylene_glycol

(any followers of Bacchus will remember:

http://en.wikipedia.org/wiki/Austrian_wine

I also seem to remember that BAA had problems deaking
with the (glycol containing) run-off from jet plane de-icing fluids.


Title: Re: Brine antifreeze?
Post by: mespilus on September 22, 2010, 12:11:51 AM
No affiliation with this supplier,
it just scrolled across as a suggestion from Googlemail:

http://www.glycols.co.uk/coolflowdtx.html

supposedly non-toxic ethylene glycol based heat transfer fluid.


Title: Re: Brine antifreeze?
Post by: Philip R on September 22, 2010, 12:20:25 AM
Are there any other isomers to discuss?

As an aside, with respect to the Austrian wine, on a skiing holiday in 1991 in Austria, the white wine was very sweet. I did not freeze up on the mountain although it was very cold, must have been the EG in the wine!!

Old off white wine makes good washer fluid for the car. Only problem being the smell of the wine enterring the car when operating the washer wipers. Could one get a high blood alcohol reading if stopped by police immediately after cleaning windscreen with said concoction?!!!

Aircraft deicing fluid falls onto the apron and is would end up in the drain interceptor. I do not know if it is separated for reuse?

On a recent flight home from Germany, the plane was sprayed with said fluid, looked like a syrupy jelly. On take off and well into the flight it streaked along the wings and dripped off.


Title: Re: Brine antifreeze?
Post by: Philip R on September 22, 2010, 12:25:49 AM
I read about this non toxic EG while ponderring an answer to your earlier comments.

An additional chemical has been added to detoxify the EG. If that chemical were to degrade, the EG may become toxic again, I do not know.

It would be best to treat the EG with appropriate safeguards as before.


Title: Re: Brine antifreeze?
Post by: mespilus on September 22, 2010, 01:00:59 AM
There is:

http://en.wikipedia.org/wiki/Triethylene_glycol


Title: Re: Brine antifreeze?
Post by: renewablegraduate on December 28, 2010, 07:17:10 PM
As far as I know the reason for antifreeze is to  prevent freezing when the system is static.    Once the water is flowing  it won't be freezing except  possibly  on exiting the heat exchanger and of course if the pump stops ice will form.  It cannot freeze when moving.    It is  advisable to  put in some antifreeze anyway.  I presume you can use  ethylene glycol as used for cars and costs about 2 per litre.                 


specialist brine anti freeze is needed , you should not use normal anti freeze, you need specially made types that have less effects to the ground when purging and filling etc


Title: Re: Brine antifreeze?
Post by: baker on December 30, 2010, 09:57:50 PM

 I use a non toxic standard  food grade anti freeze
which is good to -10  and can be damaged at high temp if you have a high temp back up
most non toxic  intifreeze start to gel at very low temperature's so your ground loop must have a flow sensor
should their be a pump failure or bad design or  diy
the anti freeze for auto industry have good properties but their is a risk of toxic anti freeze in ground loop  contamination
the heating Circe
i have changed lots of hot water cylinders with leaking heating coils so it can happen
john



Title: Re: Brine antifreeze?
Post by: titan on December 31, 2010, 10:18:53 AM
From what I have read brine is suitable for GSHP ground loops and works perfectly well with something like a 20% salt solution giving protection down below -20 degC . The salt also improves the heat transfer properties. The name brine seems to be  now used for any fluid used in the loop more usually antifreeze. For a DIY setup it could be a decent saving over the far more expensive specialist aintifreezes.


Title: Re: Brine antifreeze?
Post by: baker on December 31, 2010, 08:46:18 PM

Hi
 do you think in the ground loop salt is corrosive can you post the  link that  support the salt in ground loop
as we pay 20 for 5 ltr
if i am  called out and find salt in the loop can i test the consentration with my rf meter ?
 
salt and hydrocarbons could it crystallise in time?
their is also a stainless steel plate  heat exchanger in the circuit
 some copper pipe .  brass, and cast iron pump housing how would they do ?
 
regards
john
   


Title: Re: Brine antifreeze?
Post by: titan on January 01, 2011, 10:20:29 AM

Hi
 do you think in the ground loop salt is corrosive can you post the  link that  support the salt in ground loop



Hi John,

I can't find the exact article I have read so much on heat pumps over the last month but here is link where it is mentioned   www.rehau.co.uk/downloads.shtml        .I don't know the definitive answer regarding corrosion but I would not think it is a major problem with mdpe and a stainless heat exchanger most pumps are cast iron with stainless or plastic impellers  it would be worth getting some impartial advice ( John Cantor maybe) which may be difficult when the people with the information are trying to sell their products.  It may even be possible to incorporate a simple sacrificial anode  within the flow somewhere. It was just a suggestion for a DIY system as I would think any MCS installer will insists on a glycol based product.

I have edited it to try to get the link to work it is number 5 on the download list

Just found this link to a  WRB09  mentioning common salt for the ground loop   www.raine-or-shine.com/shop/index.php?main_page=product_info&cPath=27&products_id=276


Title: Re: Brine antifreeze?
Post by: titan on January 01, 2011, 10:36:07 AM
If you Google for salt water in GSHP ground array and not brine there are lots of hits


Title: Re: Brine antifreeze?
Post by: titan on January 01, 2011, 12:28:54 PM
It is actually mentioned on this forum in the heat pump section of the shop  www.navitron.org.uk/page.php?id=52&catId=96


Title: Re: Brine antifreeze?
Post by: wrigpm on January 01, 2011, 01:07:23 PM
People need to bear in mind that the generic term 'stainless steel' is not sufficient to ensure that it will not rust.  Unless the 'stainless steel' items are made from A4/316 (which has added anti-rust molybdenum) then in salt/Chloride environments rusting is possible.  Do we know what grade of stainless is in the PHE of the WRB series?  I chose the 'expensive' antifreeze as I did not fancy finding out the hard way!


Title: Re: Brine antifreeze?
Post by: sam123 on January 01, 2011, 04:00:13 PM
You should use 30% http://en.wikipedia.org/wiki/Ethyl_alcohol on your ground loop. It gives you -19 degree antifreeze capacity.

Earlier days also methanol was used, but it is now a days forbidden as toxic chemical :http://en.wikipedia.org/wiki/Methanol







Title: Re: Brine antifreeze?
Post by: titan on January 01, 2011, 05:44:32 PM
Do we know what grade of stainless is in the PHE of the WRB series? 

I don't but two UK suppliers are saying salt water (brine ) is acceptable in their units. I assume it is translated from Chinese but under UK consumer law I would think if there was a corrosion issue you would have some grounds for recompense. I am sure it would be easy enough to check with the manufacturer.


Title: Re: Brine antifreeze?
Post by: Baz on January 01, 2011, 07:05:49 PM
How about a differe3nt salt - it doesn't have to be sodum chloride, though it is the cheapest. Epsom salts might work as well and is relatively cheap.


Title: Re: Brine antifreeze?
Post by: Countrypaul on January 01, 2011, 07:39:42 PM
If you did use epsom salts (MgSO4) bear in mind that you will need about twice as much for the same frost protection due to its higher MW. (MgSO4 about 120, NaCL about 58.5).

Paul